The present invention relates to an apparatus for homogenizing light in accordance with the preamble of claim 1 and to a laser apparatus for producing a linear intensity distribution in a work plane in accordance with the preamble of claim 7.
An apparatus of the aforementioned type is known from US 2004/0130790 A1. The apparatuses for homogenizing light which are described therein have lens arrays in which a multiplicity, in particular all of the lenses are different from all the other lenses with regard to aperture, focal length and, if appropriate, further parameters. A good homogenization of the light is achieved by means of an in particular random distribution of these different lenses in the array.
A further homogenizing apparatus is known from WO 2005/085935. In the apparatus described therein, a multiplicity of biconvex cylindrical lenses are arranged alongside one another in a lens array, wherein each of the lenses is of the same size and has the same focal length. With an apparatus of this type, an intensity distribution referred to as “top hat” can be obtained in a work plane. Such an intensity distribution has a very good homogeneity and very steep edges, for example.
For specific application, however, it may be desirable for the falling edges to have a defined gradient. This can be achieved by defocusing in homogenizers in accordance with the prior art. In this case, however, the intensity profile generally deteriorates and it is difficult to control. One application of this is for example long combined lines such as are intended to be produced with the laser apparatus mentioned in the introduction.
In accordance with the prior art, long laser lines having a length greater than 100 mm, for example, are produced only by means of a correspondingly large distance between light source and line. In this case, the distance is typically at least as large as the length of the line. So much space is often not available in industrial applications, particularly with line lengths of more than one meter.
A laser apparatus of the type mentioned in the introduction is known from U.S. Pat. No. 6,717,105 B1. The laser apparatus described therein comprises a plurality of laser light sources which are each assigned an optical means. The optical means shape laser beams with a linear intensity distribution in each case from the laser light from the laser light sources, wherein these individual laser beams can be superimposed in a work plane to form a common linear intensity distribution.